Though the history of plate tectonics now provide us with a *modus
operandi*, they still seem to me to be a periodic phenomenon. Nothing is
world-wide, but everything is episodic. In other words the history of any
part of the earth, like the life of a soldier, consists of long periods of
boredom and short periods of terror.
-- Derek Victor Ager (1923-1992, British geologist) in "The nature of the
Stratigraphical Record, 3rd edn" (1993),141